java - 将鼠标悬停在 JSplitPane 分隔线上时更改光标

Question

当我将鼠标悬停在 JSplitPane 分隔线上时，我需要更改光标。这纯粹是为了提高可用性。我发现了两种方法来实现这一目标。代码如下所示

方法01

BasicSplitPaneUI basicSplitPaneUI = (BasicSplitPaneUI)splitPane.getUI();
BasicSplitPaneDivider divider = basicSplitPaneUI.getDivider();
divider.setCursor(new Cursor(Cursor.E_RESIZE_CURSOR));

方法02

Component divider = splitPane.getComponent(2);
divider.setCursor(new Cursor(Cursor.E_RESIZE_CURSOR));

我的问题是，如果 JSplitPane 的顶部容器是 JFrame 或 JWindow，这两种方法都会按预期工作。为了进行测试，我编写了一小段代码，其中将 JSplitPane 添加到 JPanel，然后将其添加到 JFrame。当鼠标悬停在分隔线上时，光标会按预期发生变化。

但是我正在为 intellij 开发一个 Tool Window 插件，其中 JSplitPane (包含在 JPanel 中)被添加到ToolWindow 容器。在这种情况下，当我将鼠标悬停在分隔线上时，光标保持不变。

下面是我为模拟上述场景而编写的一些测试代码。

案例01

public class Main {

public static void main(String args[]){

    JFrame f = new JFrame();
    f.setLayout(new BorderLayout());

    //PanelWithSplitPane extends JPanel. Builds the JSplitPane
    PanelWithSplitPane viewer = new PanelWithSplitPane();
    f.add(viewer, BorderLayout.CENTER);

    f.pack();
    f.setVisible(true);
    }

}

输出:按预期工作。当光标悬停在分隔线上方时会发生变化

案例02:Intellij插件

注意:这是一个intellij插件项目，其中toolWindow扩展在plugin.xml文件中指定。基本上，当工具窗口在 IDE 中打开时，就会执行 createToolWindowContent 方法。 View 和任何进一步的用户交互都从这里处理。

public class TestPane implements ToolWindowFactory {

//this method gets called when the toolWindow is opened in the IDE
@Override
public void createToolWindowContent(Project project, ToolWindow toolWindow) {
   PanelWithSplitPane viewer = new PanelWithSplitPane();
   toolWindow.getComponent().add(panel);
}
}

输出:未按预期工作。当光标悬停在分隔线上方时保持不变

PanelWithSplitPane 代码

public class PanelWithSplitPane extends JPanel {

public PanelWithSplitPane() {
    this.setLayout(new BorderLayout());

    JSplitPane splitPane = new javax.swing.JSplitPane();
    splitPane.setBorder(null);
    splitPane.setDividerLocation(1300);
    splitPane.setDividerSize(6);
    splitPane.setContinuousLayout(true);
    splitPane.setOneTouchExpandable(true);

    BasicSplitPaneUI basicSplitPaneUI = (BasicSplitPaneUI)splitPane.getUI();
    BasicSplitPaneDivider divider = basicSplitPaneUI.getDivider();
    divider.setCursor(new Cursor(Cursor.HAND_CURSOR));

    this.add(splitPane);
}

}

Answer 1

• 例如，通过使用 MouseListener 及其方法 mouseEntered/mouseExited(通过将 Cursor 返回到默认值)

• 请注意，我无法删除黑色矩形(在运行时创建的不需要的绘画制品，当移动分隔线时，您可以在左侧看到它)

import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTable;
import javax.swing.plaf.basic.BasicSplitPaneDivider;
import javax.swing.plaf.basic.BasicSplitPaneUI;

public class JSplitPaneToy {

    private JSplitPane sp;

    public JSplitPaneToy() {
        sp = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, makePanel(), makePanel());
        /*SplitPaneUI ui = sp.getUI();
         if (ui instanceof BasicSplitPaneUI) {
         ((BasicSplitPaneUI) ui).getDivider().setBorder(null);
         }*/
        BasicSplitPaneUI l_ui = (BasicSplitPaneUI) sp.getUI();
        final BasicSplitPaneDivider l_divider = l_ui.getDivider();
        l_divider.addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                Dimension l_pane_size = sp.getSize();
                if (sp.getOrientation() == JSplitPane.HORIZONTAL_SPLIT) {
                    int l_new_loc = sp.getDividerLocation() + e.getX();
                    if (l_new_loc >= 0 && l_new_loc <= l_pane_size.width) {
                        sp.setDividerLocation(l_new_loc);
                    }
                } else {
                    int l_new_loc = sp.getDividerLocation() + e.getY();
                    if (l_new_loc >= 0 && l_new_loc <= l_pane_size.height) {
                        sp.setDividerLocation(l_new_loc);
                    }
                }
            }
        });
        l_divider.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseEntered(MouseEvent e) {
                l_divider.setCursor(new Cursor(Cursor.E_RESIZE_CURSOR));
            }

            @Override
            public void mouseExited(MouseEvent e) {
                l_divider.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
            }
        });
        sp.setBorder(BorderFactory.createEmptyBorder());
        /*sp = new JSplitPane(JSplitPane.VERTICAL_SPLIT, makePanel(), sp);
         ui = sp.getUI();
         if (ui instanceof BasicSplitPaneUI) {
         ((BasicSplitPaneUI) ui).getDivider().setBorder(null);
         }
         sp.setBorder(BorderFactory.createEmptyBorder());
         sp = new JSplitPane(JSplitPane.VERTICAL_SPLIT, makePanel(), sp);
         ui = sp.getUI();
         if (ui instanceof BasicSplitPaneUI) {
         ((BasicSplitPaneUI) ui).getDivider().setBorder(null);
         }
         sp.setBorder(BorderFactory.createEmptyBorder());
         sp = new JSplitPane(JSplitPane.VERTICAL_SPLIT, makePanel(), sp);
         ui = sp.getUI();
         if (ui instanceof BasicSplitPaneUI) {
         ((BasicSplitPaneUI) ui).getDivider().setBorder(null);
         }
         sp.setBorder(BorderFactory.createEmptyBorder());*/
        JFrame frame = new JFrame("JSplitPane Toy");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(sp);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        /*try {
         for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
         if ("Nimbus".equals(info.getName())) {
         javax.swing.UIManager.setLookAndFeel(info.getClassName());
         break;
         }
         }
         } catch (ClassNotFoundException ex) {
         } catch (InstantiationException ex) {
         } catch (IllegalAccessException ex) {
         } catch (javax.swing.UnsupportedLookAndFeelException ex) {
         }*/
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JSplitPaneToy jSplitPaneToy = new JSplitPaneToy();
            }
        });
    }

    private JScrollPane makePanel() {
        JScrollPane pane = new JScrollPane(new JTable(
                new Object[][]{{0, 1, 2}, {1, 2, 3}, {2, 3, 4}}, new Object[]{1, 2, 3}) {
                    private static final long serialVersionUID = 1L;
                });
        pane.setPreferredSize(new Dimension(200, 100));
        return pane;
    }
}